JPH1165193A - Paper sheet post-processing device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a paper sheet post-processing device capable of successively executing the post-processing even if the paper sheet with different size is fed out of an image forming device and holding a loading state of the paper sheet. SOLUTION: This device stores the minimum size of a paper sheet which is already loaded on a stack tray 61, compares this minimum size with the size of a succeeding paper sheet fed out of an image forming device, makes the image forming device feed out the paper sheet when the size of the paper sheet being fed out of the image forming device is below the size of one size larger than the minimum size, matches a set of a specified number of the paper sheets by a paper sheet collecting paddle 14 and a matching plate 15, while discharging the paper sheet on a compiling tray 13 through a paper sheet transporting path 11 and loads the paper sheets on the stack tray 61, after executing the post-processing to the set by a paper sheet post-processing machine 21.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sheet post-processing apparatus for aligning and stacking sheets sent from an image forming apparatus, and more particularly, to comparing the size of stacked sheets and the sheet sent from the image forming apparatus. The present invention relates to a sheet post-processing apparatus that controls the stacking of sheets according to the result, thereby improving post-processing efficiency.

[0002]

2. Description of the Related Art In an image forming apparatus such as a copying machine, a printer, a facsimile or the like, a sheet after image formation, which is connected to each apparatus and output from each apparatus, is a predetermined number of sheets (hereinafter referred to as "set"). )), And after performing post-processing such as binding or punching for each set automatically,
2. Description of the Related Art There is known a sheet post-processing device that discharges a sheet to a stacking tray.

Japanese Patent Application Laid-Open No. Hei 8-091686 discloses a conventional technique of this kind. In the known document, a predetermined number of sheets of image-formed sheets sent from an image forming apparatus are stored in an editing tray. Then, the traveling direction of the accumulated paper set is aligned with a paper-adjusting paddle, the sides are aligned with a paper alignment plate, and then stapling or punching is performed.
A paper post-processing device that discharges to a stacking tray is disclosed.

[0004]

However, when a large number of sheets (for example, 1000 sheets or more) of different sizes are stacked on the stacking tray of the above-described conventional sheet post-processing apparatus, a difference in the center of gravity between the sheets is caused. The loaded state cannot be maintained.

[0005] The above-mentioned state becomes conspicuous when the size of sheets stacked below the stacking tray is small and the size of sheets stacked above is large. In particular, when the size difference between the stacked sheets is large, there is a problem that large-sized sheets stacked above the stacking tray are displaced, and the stacked state is collapsed.

In order to avoid this problem, in a conventional sheet post-processing apparatus, when a job for outputting sheets of different sizes is executed in the image forming apparatus, the sheets of different sizes stacked on the stacking tray are removed. The job is suspended until all the sheets are removed from the stacking tray, and then the sheets are output.

However, in the above-described solution, the image forming apparatus cannot output the sheets even when the sheets can be sufficiently stacked on the stacking tray. And the user's demand to output a large amount of paper on which images have been formed cannot be sufficiently satisfied.

Therefore, the present invention can continuously execute post-processing even when sheets of different sizes are sent out from the image forming apparatus, and can maintain a stacked state of sheets. An object of the present invention is to provide a sheet post-processing device.

[0009]

According to one aspect of the present invention, there is provided an image forming apparatus for forming an image, comprising: a sheet sending control unit for controlling sending of a sheet after image formation; Sheet aligning means for accumulating and aligning a predetermined number of sheets sent out, sheet discharging means for discharging sheets aligned by the sheet aligning means, and sheet stacking means for sequentially stacking sheets discharged by the sheet discharging means. In the paper post-processing apparatus provided, a paper size storage means for storing a size of paper sequentially loaded by the paper loading means, a smallest one of the paper sizes stored by the paper size storage means, and the image Paper size comparing means for comparing the size of the paper sent from the forming apparatus, wherein the paper sending control means As a result of the comparison, the size of the sheet after image formation from the image forming apparatus is smaller than the smallest one of the sheet sizes stored by the sheet size storage unit, or the sheet of the predetermined size. Only when it is within the range, the image forming apparatus is caused to send out the sheet.

According to a second aspect of the present invention, in the first aspect of the present invention, the sheet sending control unit includes a sheet sending unit that stores the size of the sheet sent from the image forming apparatus by the sheet size storing unit. Paper is sent from the image forming apparatus only when the size is equal to or smaller than the smallest size or one size above the smallest size.

According to a third aspect of the present invention, in the first or second aspect of the invention, the sheet sending control means includes a sheet size sent from the image forming apparatus and a sheet size storing means. If the conditions for output are not satisfied, the order of the jobs output from the image forming apparatus is skipped, and the paper for the next output job is sent out. And

According to a fourth aspect of the present invention, in the first to third aspects of the present invention, the stacked number storage means for storing the number of sheets stacked by the sheet stacking means, and the stacked number storage means. Paper number comparing means for adding the number of sheets stored by the above and the number of sheets output to the next job, and comparing the addition result with the total number of sheets that can be stacked by the sheet stacking means. The image forming apparatus further includes a sheet sending control unit that causes the image forming apparatus to send a sheet according to a result of the comparison by the sheet number comparing unit.

According to a fifth aspect of the present invention, in the fourth aspect of the present invention, the sheet sending control unit determines that the addition result is equal to or less than the total number of sheets that can be stacked by the sheet stacking unit. The sheet is sent from the image forming apparatus only when the sheet is transmitted.

According to a sixth aspect of the present invention, in the fifth aspect of the invention, the sheet stacking means includes a plurality of stack trays for stacking sheets, and the sheet size storage means includes The size of the sheets stacked for each stack tray is stored, the stacked number storage unit stores the number of sheets stacked for each stack tray, and the sheet size comparison unit is set for each stack tray. The sheet size stored by the sheet size storage unit is compared with the size of the sheet sent from the image forming apparatus, and the sheet number comparison unit stores the stacked sheet number storage unit for each stack tray. The added number of sheets and the number of sheets output to the next job are added, and the addition result and the sheet can be stacked by the sheet stacking unit. And the sheet discharge control means discharges the sheet to be output to the next job to a stack tray on which sheets closest to the size of the sheet sent from the image forming apparatus are stacked. And

According to a seventh aspect of the present invention, in the first to sixth aspects, the sheet stacking means is
The sheet stacking unit further includes a sheet presence / absence detecting unit that detects whether a sheet is stacked on the sheet stacking unit, and the sheet sending control unit is configured to output the sheet from the image forming apparatus when no sheet is stacked on the sheet stacking unit. It is characterized in that paper is sent out.

[0016]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a sheet post-processing apparatus according to the present invention will be described below in detail with reference to the accompanying drawings.

The sheet post-processing apparatus 72 according to the present invention is shown in FIG.
As shown in FIG. 1, a paper transport path 11 for passing the paper sent from an image forming unit (not shown), an exit sensor 17 provided in the paper transport path 11 for detecting the passage of the paper, a paper transport path 11, a paper discharge roller 12 for discharging the paper that has passed through the paper conveyance path 11, a compile tray 13 for storing the paper discharged by the paper discharge roller 12, and alignment of the paper stored in the compile tray 13 in the traveling direction. Sheet aligning paddle 14, a sheet aligning plate 15 for aligning the sides of the accumulated sheets, a sheet positioning motor 16 for driving the sheet aligning plate, and a sheet post-processing machine 21 for automatically binding the aligned sheets. And a set discharging device 30 that discharges the aligned sheets as a set
And a pinch roll 32 constituting the set discharging device 30;
A leaf spring 33, a shaft 34 and a spring 38, a stack tray 61 on which a set ejected by the set ejection device 30 is stacked, and a sheet presence / absence detection sensor 6 for detecting whether or not sheets are stacked on the stack tray 61.
3

As shown in FIG. 1, the A3 set 26, the B4 set 25, the A4 set 24, and the B5 set are set on the stack tray 61 as shown in FIG. The set 23, the A5 set 22, the B5 set 23, the B5 set 23, and the A5 set 22 are stacked in this order.

FIGS. 2 and 3 show a detailed configuration of the set discharging device 30. FIG. Here, FIG. 2 is a side view of the set discharging device 30, and FIG. 3 is a front view of the set discharging device.
FIG. 2 shows a state before the A4 set 24 is aligned.

As shown in FIGS. 2 and 3, the set discharging device 30 includes a bearing 3 serving as a bearing for a shaft 34.
1, a leaf spring 33 serving as a support plate for the pinch roll 32,
A shaft 34 for holding the pinch roll 32;
3 and a pressing guide 35 for guiding the pressing,
7, a pinch nip motor 36 for rotating the cam roller 37, and a pressing guide 35.
Roller 37 for controlling the ascending and descending of the pinch roll, a spring 38 for powering up the leaf spring 33 when the pinch roll is raised, a stopper 39 for determining the raised position of the pinch roll 32, and a spring indicating pin 40 for holding the spring 38 And the frame 4 for fixing the bearing 31
2, an encoder 43 that detects the rotation of the pinch nip motor 36, an up sensor 44 that detects that the pinch roll 32 is at the raised position, and a down sensor 45 that detects that the pinch roll 32 is at the lowered position. Set discharge roller 5 for discharging a set of aligned sheets
1, a driven pulley 52, a driving pulley 53, a belt 54, and a discharge motor 5 for rotating the set discharge roller.
5 is comprised.

The sheet post-processing device 7 configured as described above
FIG. 5 shows a control system for controlling the control system 2.

As shown in FIG. 5, the sheet post-processing device 72
Is a main control unit 1 which controls the control of each control unit shown in FIG.
00 and a paddle control unit 1 that controls the sheet shifting paddle 14
02 and an alignment plate control unit 103 for controlling the paper alignment plate 15
Discharge control unit 1 for controlling the set discharge device 30
04 and a post-processing control unit 10 that controls the sheet post-processing machine 21
5, a sheet take-in control unit 106 that controls the taking-in of sheets sent from the image forming unit 100, a stack sheet storage unit 107 that stores the size and number of sheets stacked on the stack tray 61, A paper presence / absence detection sensor control unit 108 for controlling the detection sensor 63 is provided, and each unit is connected to the main control unit 100 via a control line.

The main control unit 100 includes the image forming unit 10
Both are connected by a control line, and can control the image forming unit.

Next, the operation of the above-described sheet post-processing apparatus for aligning the sheets sent from the image forming apparatus and stacking the sheets as a set will be described with reference to FIG. FIG. 6 is a flowchart showing the operation flow of the sheet post-processing apparatus.

First, when a sheet on which an image has been formed is sent from the image forming apparatus in the direction C shown in FIG. 1, the sheet passes through the exit sensor 17 via the sheet conveying path 11. Then, the exit sensor 17 is controlled by the main control unit 10.
The main control unit 100 notifies that the sheet has passed at 0 and instructs the sheet take-in control unit 106 to rotate the sheet discharge roller 12. Upon receiving this instruction, the paper take-in control unit 106 rotates the paper discharge roller 12 and discharges the paper to the compile tray 13 (Step 201 in FIG. 6).

The main control unit 100 stores the size of the paper in the stack paper storage unit 107 when the paper is discharged (step 202), and is provided in the storage unit and stored in the compile tray 13. The value of the number storage register for storing the number of sheets is incremented (step 2).
03). The value stored in the stack paper storage unit 107 is
It is reset when all the sheets are removed from the stack tray 61.

When the sheet is discharged to the compile tray, the main controller 100 instructs the paddle controller 102 and the aligning plate controller 103 to align the sheets.

Upon receiving this command, the paddle control unit 102
By rotating the paper shift paddle 14 and aligning the leading edge of the accumulated paper, the alignment plate control unit 103 drives the paper alignment plate 15 by rotating the paper positioning motor 16 to adjust the side of the accumulated paper. Match (step 204).

Thereafter, the main control unit 100 determines whether or not the value of the register has reached the predetermined number of sets (step 205). The output of the sheet is instructed, and the sheet is discharged again to the compile tray (step 201). The above operation is repeated until the value of the register reaches a predetermined set number.

When the number of sheets reaches a predetermined number, the main control unit 100 performs post-processing of the set in accordance with the post-processing control unit 105 when the sheet post-processing apparatus is set to the post-processing mode. After receiving the command, the post-processing control unit 105 activates the sheet post-processing machine 21 to perform a binding process on the set (step 207).

If the sheet post-processing apparatus is not set to the post-processing mode, the flow advances to step 208 to discharge the set to the stack tray 61.

When the post-processing of the paper is completed, the main controller 10
0 instructs the set discharge control unit 104 to discharge the set. Upon receiving this command, the set discharge control unit 104
By rotating the pinch nip motor 36 shown in FIG. 3, the cam roller 37 is brought into sliding contact with the concave portion 35a, and the leaf spring 33 is lowered.

At this time, the set discharge control unit 104 receives the rotation signal from the encoder 43 and
Is stopped to the position where the A4 set 24 is pressed, the rotation of the pinch nip motor 36 is stopped. Then, a pinch roller down sensor 4 for detecting the lowering of the pinch roller 32
5 is turned ON, and the sheet post-processing device 72 enters the state shown in FIG. In this state, the cam roller 37 presses the pressing guide 35, and pressure is applied to the A4 set 24 from the pinch roll 32 via the leaf spring 33. Next, the set discharge control unit 104 drives the drive pulley 53 by rotating the discharge motor 55, and rotates the discharge roller 51 via the belt 54 and the driven pulley 52. As a result, the A4 set 24 is discharged to the stack tray 61 (Step 208), and is stacked on the stack tray 61 (Step 209).

When the A4 set 24 is discharged, the set discharge control unit 104 rotates the pinch nip motor 36 to raise the leaf spring 33.

At this time, the set discharge control unit 104 receives the rotation signal from the encoder 43 and
Rises to the position shown in FIG.
The rotation of No. 6 is stopped. The raised position of the pinch roller 32 is held by the stopper 39. In this state, the pinch roller up sensor that detects the rise of the pinch roller 32 is turned on.

If there is still a job for the image forming apparatus, the main control unit 100 returns to step 201 and repeats the above operation.

FIG. 7 is a timing chart showing the operation of the sheet post-processing apparatus according to the present invention.

FIG. 7 shows the input of the operation of the sheet post-processing apparatus according to the present invention from the sheet take-in to the alignment, and the operation from the subsequent processing to the discharge of the set when post-processing is performed. Classification into post-processing control and non-post-processing control that indicates the operation until the set is discharged when post-processing is not performed, and turns on / off the operation of each part
It is expressed by

In the input operation in FIG. 7, the exit sensor 17 is turned on each time a sheet passes through the sensor, and when the N-th sheet, which is a set of sheets, is detected, the exit sensor 17 is turned on after a lapse of time T0. The pinch nip motor 36 rotates.

When the pinch nip motor 36 rotates, the pinch roller up sensor for detecting the rise of the pinch roller turns off, the pinch roller down sensor for detecting the drop of the pinch roller turns on, and the rotation of the pinch nip motor 36 stops. .

Thereafter, when post-processing is performed, T1
The time post-processing is performed, and after the end of the processing, the discharge motor 55 rotates for T2 time to discharge the set.

If no post-processing is performed, after the pinch nip motor 36 stops, the discharge motor 55
Rotates and ejects the set. At this time, the discharge motor 55
Discharges the set over T1 + T2 hours while changing the rotation speed.

After the set is discharged, the pinch nip motor 3
6, the pinch roller up sensor is turned on, and the pinch roller down sensor is turned off.

Then, the number of sheets passing through the exit sensor 17 is counted until the next set is accumulated again.

The sheet post-processing apparatus according to the present invention is characterized in that, in addition to the operation described above, the discharge to the stack tray 61 is controlled in consideration of the size or the number of sheets stacked on the stack tray 61. .

A characteristic operation example of the sheet post-processing apparatus according to the present invention will be described below with reference to FIGS.

FIG. 8 compares the paper sent from the image forming apparatus (hereinafter referred to as "printout") with the paper stacked on the stack tray, and controls the discharge to the stack tray 61 according to the result. 9 is a flowchart illustrating an operation example in the case.

First, the main control unit 100 operates as the image forming unit 101.
(Step 301), the sheet presence / absence detection sensor 63 detects whether or not sheets are stacked on the stack tray 61, and notifies the main control unit 100 of the result.

The main controller 100 determines whether or not sheets are stacked on the stack tray based on the notification (step 302). If no sheets are stacked, the process proceeds to step 306 and prints out. .

When the sheets are stacked, the stack sheet storage unit 107 and the image forming unit 101 are accessed, and the size of the smallest sheet among the sheets stacked on the stack tray 61 (hereinafter referred to as “minimum size”) ) And the size of the paper to be printed out, and compare them (step 303).

The size of the paper to be printed out is equal to or smaller than the minimum size of the paper stacked on the stack tray 61 or one size higher than the minimum size (for example, if the minimum size is "A4", one size is set). Only when the upper size is “B4” (hereinafter, the size of the sheet satisfying such an allowable condition is referred to as “allowable size”), printout is executed (step 306).

As described above, the allowable size is defined as “a size equal to or smaller than the minimum size or one size higher than the minimum size” in consideration of the capacity of a commonly used stack tray, if the size is one size smaller than the minimum size. This is because even if a large amount is loaded, the loading state is not affected.

If the size is any other size, the process waits until the sheet is removed from the stack tray 61 (step 305).

The comparison of the sizes described above indicates that the size of the sheet printed out from the image forming apparatus is “A5”, “B”.
5 "," A4 "," B4 "," A3 ", in which the size increases in this order, and the allowable size is" a size equal to or less than the minimum size or one or two above the minimum size ". Is also possible.

Further, the size of the paper is specified in millimeters, and the allowable size is set to "the size of the paper to be printed out is not larger than the size of the paper stacked on the stack tray 61 by 20 mm in height and 10 mm in width. ].

That is, the user can arbitrarily set the allowable size of the sheet to be discharged to the stack tray 61 according to the stacking capacity of the stack tray 61.

After the printout in step 306, the sheet is discharged to the stack tray 61 according to the flow shown in FIG. 6 (step 307).

FIG. 9 shows a case where the image forming apparatus has a plurality of print jobs,
9 is a flowchart illustrating an operation example when determining which job is to be executed in accordance with the size of sheets stacked on a sheet.

In FIG. 9, first, when the main control unit 100 instructs the image forming unit 101 to print out (step 401), the sheet presence / absence detection sensor 63 detects whether or not sheets are stacked on the stack tray 61. And
The result is notified to the main control unit 100.

The main control unit 100 determines whether sheets are stacked on the stack tray based on the notification (step 402). If no sheets are stacked, the process proceeds to step 408 to execute printout. .

When sheets are stacked, the stack sheet storage unit 107 and the image forming unit 101 are accessed to read the minimum size of the sheets stacked on the stack tray 61 and the size of the sheet to be printed out. The two are compared (step 403).

As a result of the comparison, if the size of the paper to be printed out is the allowable size, the printout is executed (step 408). If the size is not the allowable size, another printout is sent to the main control unit 100. If there is no instruction (No in Step 405), the process waits until the sheet is removed from the stack tray 61 (Step 4).
07), when the paper is removed, printout is executed (step 408).

When the size of the paper to be printed out is not the allowable size and the main control unit 100 gives another printout instruction, the size of the paper to be printed out and the size of the paper to be stacked on the stack tray 61 are stacked. The sizes of the sheets are compared (step 406), and it is determined whether or not the size is an allowable size (step 404).

Here, if the size is not the allowable size, the process proceeds to step 405 again, and it is determined whether or not another printout instruction is given. As described above, when there are a plurality of printout instructions, a job in which paper of an allowable size is printed out is searched in order, and if there is a corresponding job, the job is executed.

The paper printed out from the image forming apparatus through the above processing is stacked on the stack tray 61 according to the operation flow shown in FIG. 6 (step 409).

FIG. 10 shows a comparison between the size and the number of sheets to be printed out and the number of sheets stacked on the stack tray when a plurality of stack trays are provided in the sheet post-processing apparatus according to the present invention. 9 is a flowchart illustrating an operation example when a sheet is discharged to a stack tray provided therein.

Here, an example of the configuration of the sheet post-processing apparatus provided with a plurality of stack trays will be described with reference to FIG.

FIG. 12 shows a sheet post-processing apparatus 72 having two stack trays 61 connected to the sheet post-processing apparatus shown in FIG. In the sheet post-processing device 72, the sheet conveying path 11 is branched into two, and the main control unit 100 operates the gate 18 provided at the branch point by a solenoid to load the stack on any stack tray. Control.

When the sheet whose conveyance direction is determined by the gate 18 passes through any of the exit sensors 17, the main control section 100 controls the sheet take-in control section 106 to discharge the sheet to the compile tray 13. Other operations such as sheet alignment, post-processing, and discharging are the same as those of the sheet post-processing apparatus shown in FIG.

When providing two or more stack trays,
As in the case shown in FIG. 12, the basic configuration shown in FIG. 1 is connected in multiple stages, and the conveyance of the paper is controlled by a gate. The stack trays may be provided in the vertical direction as shown in FIG. 12, or may be provided side by side in the horizontal direction.

In the operation shown in FIG. 10, in addition to the comparison of the allowable sizes performed in the operations shown in FIGS. 8 and 9, the comparison of the allowable number of sheets is performed. This comparison of the allowable number of sheets is a process for not exceeding the total amount of sheets that can be stacked on each stack tray.

Here, the main control unit 100 identifies each stack tray by a tray number represented by a positive integer, and determines a tray from which sheets are to be discharged by a tray designation register provided in the stack sheet storage unit 107. I do.

The stack sheet storage unit 107 stores the size and number of sheets stacked for each stack tray. The stored size and number are reset when all the sheets are removed from the stack tray. When a plurality of different sets are stacked, the sheet size and the number of sets are stored for each set.

In FIG. 10, first, when the main control unit 100 instructs the image forming unit 101 to print out (step 501), the sheet presence / absence detection sensor 63 detects whether or not sheets are stacked on the stack tray 61. ,
The result is notified to the main control unit 100.

The main control unit 100 determines whether sheets are stacked on the stack tray having the tray number 1 based on the notification (step 502). If no sheets are stacked, the process proceeds to step 507. Execute printout.

If sheets have been stacked, the stack sheet storage unit 107 and the image forming unit 101 are accessed, and the size of the sheets stacked on the stack tray having the tray number 1 and the size of the sheet to be printed out are accessed. And compare the two. At the same time, the number of sheets to be output to the next job is added to the number of sheets stacked on the stack tray having the tray number of 1, and the addition result is compared with the total number of sheets that can be stacked on the stack tray ( Step 503).

As a result of this comparison, if the size of the paper to be printed out is not the allowable size (No in step 504), or the result of the addition is equal to or less than the number of sheets that can be stacked on the stack tray (hereinafter, this condition is referred to as “allowable number”) If not (No in step 505), the tray number is incremented, and the process returns to step 502 to check whether or not there is a sheet in the stack tray having the tray number of 2.

The above operation is repeated, and if there is a stack tray satisfying the allowable size and the allowable number of sheets, printout is executed (step 507), and the set is discharged to the tray (step 508).

FIG. 11 shows a case in which the sheet post-processing apparatus according to the present invention has a plurality of stack trays, and the sheets having the size closest to the size of the sheets to be printed out are stacked on the stack tray. 5 is a flowchart illustrating an operation example when discharging the image.

In FIG. 11, first, when the main control unit 100 instructs the image forming unit 101 to print out (step 601), the sheet presence / absence detection sensor 63 detects whether or not sheets are stacked on the stack tray 61. ,
The result is notified to the main control unit 100.

The main control unit 100 determines whether or not sheets are stacked on the stack tray having the tray number 1 based on the notification (step 602). If no sheets are stacked, the process proceeds to step 608. Execute printout.

When sheets are stacked, the main control unit 100 checks the number of stacked sheets of each stack tray stored in the stack sheet storage unit 107 and determines whether or not there is another empty tray. Step 603).

If there is an empty tray, the empty tray is designated (step 604), and printout is executed (step 608).

If there is no empty tray, the stack sheet storage unit 107 and the image forming unit 101 are accessed to read the size and number of sheets stacked on each stack tray, and the conditions for the allowable size and the allowable number of sheets are read. It is determined whether there is a stack tray that satisfies the condition (Step 606).

If no stack tray satisfies the above condition, the process returns to step 602, and waits until one of the stack trays becomes empty.

If there is a stack tray that satisfies the above condition in step 606, the main control unit 100 accesses the stack sheet storage unit 107 and stores the sheet size of the stack tray that satisfies the above condition stored in the storage unit. Are compared with each other, a stack tray on which sheets of the size closest to the size of the sheet to be printed out are stacked is designated (step 607), and the printout is executed (step 607). Step 6
08).

For example, when discharging A4 paper from the image forming apparatus, when B4 paper is loaded on one stack tray and B5 paper is loaded on another stack tray, A4 paper is discharged. (Paper length: 297 mm, paper width 210 mm), B4 (paper length: 365 mm, paper width 257 mm), B5 (paper length: 257 mm, paper width 18)
The difference between the sheet length and the sheet width between each sheet of paper (2 mm) is obtained, and the difference between the sheet and the sheet having the smallest difference (in this case, the sheet length is 68 mm, the sheet width is 47 mm, and the difference from B5 is B5). A4 sheet is discharged to the stack tray on which the sheet length is 40 mm and the sheet width is 28 mm, which corresponds to B5.)

The above criterion can be configured to compare only one of the sheet length and the sheet width.
Also, depending on the shape of the stack tray, it is possible to freely change whether to prioritize the difference in paper length or the difference in paper width, or to calculate the area difference between sheets and use it as a reference for comparison. it can.

After selecting the stack tray as described above, the sheet is discharged to the designated stack tray through the operation flow shown in FIG. 6 (step 609).

[0090]

As described above, according to the present invention,
By comparing the size of the paper output from the image forming unit with the size of the paper stacked on the stack tray, and executing post-processing according to the result, the stacking capacity of the stack tray can be used effectively. it can.

Further, the number of sheets stacked on the stack tray and the number of sheets output for the next job are added, and the result is compared with the maximum number of sheets stacked on the stack tray, and post-processing is executed according to the result. By providing the means for performing the operation, the stacking capacity of the stack tray can be further effectively used.

When a plurality of stack trays are provided, a stack tray on which the sheets are stacked is selected according to the size of the sheets output from the image forming unit.
By providing the stack tray with a unit for discharging sheets, the efficiency of the job of the image forming unit can be improved.

When a plurality of stack trays are provided, the size of the paper stacked on each stack tray is compared with the size of the paper output from the image forming unit, and the size closest to the size of the paper is compared. By providing a means for discharging paper to the stack tray on which the paper is loaded, the variation in the size of the paper loaded on the stack tray is minimized, and the number of papers that can be loaded on the stack tray is increased. Can be.

With the above effects, it is possible to provide a sheet post-processing apparatus that efficiently executes post-processing of sheets.

[Brief description of the drawings]

FIG. 1 is a side view showing an embodiment of a configuration of a sheet post-processing apparatus according to the present invention.

FIG. 2 is a side view showing a state in which a set discharge device of the sheet post-processing apparatus according to the present invention is raised.

FIG. 3 is a front view illustrating a configuration of a set discharge device of the sheet post-processing apparatus according to the present invention.

FIG. 4 is a side view showing a state where the set discharge device of the sheet post-processing apparatus according to the present invention is lowered.

FIG. 5 is a block diagram showing a control mechanism of the sheet post-processing apparatus according to the present invention.

FIG. 6 is a flowchart showing a basic operation of the sheet post-processing apparatus according to the present invention.

FIG. 7 is a timing chart showing a basic operation of the sheet post-processing apparatus according to the present invention.

FIG. 8 is a diagram illustrating an operation example of the sheet post-processing apparatus according to the present invention in a case where a sheet sent from an image forming apparatus is compared with a sheet stacked on a stack tray, and discharge to the stack tray is controlled according to a result of the comparison. 5 is a flowchart showing the process.

FIG. 9 is a diagram illustrating a case where the image forming apparatus has a plurality of print jobs and determines which job is to be executed according to the size of sheets stacked on a stack tray according to the present invention. 9 is a flowchart illustrating an operation example of the processing device.

FIG. 10 is a diagram illustrating a stack having a condition when a plurality of stack trays are provided in the sheet post-processing apparatus according to the present invention, the size and the number of sheets to be printed out and the number of sheets stacked on the stack tray are compared. 9 is a flowchart illustrating an operation example of the sheet post-processing apparatus according to the present invention when discharging sheets to a tray.

FIG. 11 illustrates a case where the sheet post-processing apparatus according to the present invention includes a plurality of stack trays, and discharges a sheet to a stack tray on which sheets of a size closest to the size of the sheet to be printed out are stacked. 9 is a flowchart showing an operation example of the sheet post-processing apparatus according to the present invention in the case.

FIG. 12 is a side view illustrating a configuration when the sheet post-processing apparatus according to the present invention includes two stack trays.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 11 ... Paper conveyance path, 12 ... Paper discharge roller, 13 ... Compile tray, 14 ... Paper alignment paddle, 15 ... Paper aligning plate, 16 ... Paper positioning motor, 17 ... Exit sensor, 21 ... Paper post-processing machine, 22 ... A5 Set, 23 ...
B5 set, 24 ... A4 set, 25 ... B4 set, 2
6 A3 set, 30 set ejector, 31 bearing, 32 pinch roll, 33 leaf spring, 34 shaft, 35 holding guide, 35a recess, 36 pinch nip motor, 37 cam roller, 38 Spring, 39 ... Stopper, 40 ... Spring indication pin, 42
... frame, 43 ... encoder, 44 ... up sensor, 45 ... down sensor, 51 ... set discharge roller,
52: driven pulley, 53: drive pulley, 54: belt,
55: discharge motor; 61: stack tray; 63: paper presence / absence detection sensor; 72: paper post-processing device.

Claims (7)

[Claims] 1. An image forming apparatus for forming an image, a sheet sending control unit for controlling the sending of a sheet after image formation, a sheet aligning unit for accumulating and aligning a predetermined number of the sent sheets, and a sheet aligning unit. A sheet post-processing apparatus comprising: a sheet discharging unit that discharges the sheets aligned by the unit; and a sheet stacking unit that sequentially stacks the sheets discharged by the sheet discharging unit. Paper size storage means for storing a size; paper size comparison means for comparing the smallest size of the paper sizes stored by the paper size storage means with the size of the paper sent from the image forming apparatus. The sheet sending control unit includes: a sheet after image formation from the image forming apparatus, based on a result of the comparison by the sheet size comparing unit. And causing the image forming apparatus to send out the sheet only when the sheet size is smaller than the smallest one of the sheet sizes stored by the sheet size storage unit or within a predetermined size range. Paper post-processing device. 2. The sheet sending control unit according to claim 1, wherein the size of the sheet sent from the image forming apparatus is equal to or smaller than the smallest size of the sheet sizes stored by the sheet size storage unit. 2. The sheet post-processing apparatus according to claim 1, wherein the sheet is sent from the image forming apparatus only when the size is one size higher than the sheet size. 3. The sheet sending control unit compares the size of the sheet sent from the image forming apparatus with the size of the sheet stored by the sheet size storing unit, and determines that the output condition is not satisfied. 3. The sheet post-processing apparatus according to claim 1 or 2, wherein the order of the job output from the image forming apparatus is skipped, and the sheet of the next job that can be output is sent out. 4. A stacking number storage unit for storing the number of sheets stacked by the sheet stacking unit; and a sheet number stored in the stacking number storage unit and a sheet number output for the next job. And a sheet number comparing unit for comparing the addition result with the total number of sheets that can be stacked by the sheet stacking unit, wherein the sheet sending control unit includes a result of the comparison by the sheet number comparing unit. 4. The sheet post-processing apparatus according to claim 1, wherein a sheet is sent from the image forming apparatus in response to the condition. 5. The image forming apparatus according to claim 1, wherein the sheet sending control unit sends the sheet from the image forming apparatus only when the addition result is equal to or less than the total number of sheets that can be stacked by the sheet stacking unit. Claim 4
Paper post-processing device according to the above. 6. The sheet stacking unit includes a plurality of stack trays for stacking sheets, and the sheet size storage unit stores a size of sheets stacked for each of the stack trays, The number-of-sheets storage unit stores the number of sheets stacked for each of the stack trays, and the sheet-size comparison unit stores the sheet size stored by the sheet-size storage unit for each of the stack trays, and the image Comparing the size of the sheet sent from the forming apparatus, the sheet number comparing means, for each stack tray, the number of sheets stored by the stacked number storage means and the number of sheets output to the next job And comparing the result of the addition with the total number of sheets that can be stacked by the sheet stacking unit. Sheet post-processing device according to claim 5, characterized in that discharging the sheet closest paper size of the paper fed from the image forming apparatus is output to the next job in the stack tray stacked. 7. The sheet stacking unit includes a sheet presence detecting unit that detects whether a sheet is stacked on the sheet stacking unit, and the sheet sending control unit includes a sheet stacking unit on which sheets are stacked. If not,
The sheet post-processing apparatus according to claim 1, wherein the sheet is sent from the image forming apparatus.